Process of treating hydrocarbons



R. F. DAVIS PROCESS OF TREATING HYDROCARBONS Filed June l5 Patented ct. 27, 1931 UNITED STATES PATENT OFFICE RICHARD F. DAVIS, OF BERKELEY, CALIFORNIA, ASSIGN OR, BY M ESNE ASSIGNMENTS, T STANDARD OIL COMPANY 0F CALIFORNIA, 0F SAN FRANCISCO, CALIFORNIA, A

CORPORATION OF DELAWARE PROCESS OF TREATING HYDROCARBONS Application led Junev 15,

This invention relates, in general, to the hydrogenation of hydrocarbons or, in other words, to cracking processes in which hydrogen is supplied during the breaking up of the heavier hydrocarbons so as to produce relatively large amounts of lighter hydrocarbons. More particularly the invention relates to those processes in which hydrogenation 1s effected without employing extraneous hydro en, by which term is meant hydrogen 1ntro ucedas a gas from a source outside of the process.

One of the principal objects of this invention is. to effect hydrogenation in liquid phase using the lighter saturated hydrocarbons o the parafn series, as, for example, propane, butane, and pentane, as the source of the hydrogen. This will be better understood if it be considered that the liquid phase condition is possible to a considerable degree, even though the lighter saturated hydrocarbons, when by themselves have critical temperatures below the cracking temperature of the oil being treated, because the lighter hydrocarbons are quite soluble in the heavy hydrocarbon even at the cracking temperature of 7 50 to 800 F. The lighter the hydrocarbon the less its solubility according as the carbon atoms decrease in number, but even methane has a very much greater solubility than hydrogen under the same conditions and hence the more intimate contact is secured. Thus there is more complete and intimate contact through solubility. `TIL-his distinguishes the present processes from those prior processes of hydrogenation in which a liquid-vapor phase system obtains.

More particularly, an important object is the production of a synthetic crude by cracking a mixture of the lighter hydrocarbons referred to above and the heavier hydrocarbons while the lighter and heavier hydrocarbons are in the liquid phase so that a more intimate contact will take place between the lighter and heavier hydrocarbons during the cracking operation than would be possible if one of said hydrocarbons were in the liquid phase and the other in the gaseous phase.

This process is also distinguished from those prior processes in which cracking of 1925. Serial No. 37,175.

heavier hydrocarbons or crude petroleum is effected in liquid phase without at the same time having theseheavier hydrocarbons in intimate contact with lighter liquid hydrocarbons relatively high in hydrogen.

This process depends upon the four recognized basic factors in present day cracking processes, to-wit; temperature, pressure, time, and degree of concentration of the reacting constituents, namely, the carbon and hydrogen of the petroleum.

It is well known in the art relating to the cracking of petroleum that hydrocarbons tend to dissociate into their elements, carbon and hydrogen, when proper conditions obtain, the dissociation proceeding to an extent commensurate With the severity of the conditions imposed. For example, the dissociation of petroleum hydrocarbons vtends more toward completion, as the temperature and time increase, the pressure decreases and the ratio of hydrogen to carbon decreases. Owing to the .fact that, when hydrocarbons are dissociated or cracked by the prior known processes, there tends to be formed an intermediate series of compounds having different ratios of carbon and hydrogen, it has been possible to obtain comparatively small yields of hydrocarbon compounds within a limited range of 4boiling points and, therefore, suitable for use as fuel in internal combustion motors.' The most characteristic feature of the dissociations in the prior processes, however, is the relatively high loss of hydrogen in the form of gas, indicating that a relatively large amount of hydrogen-carbon union has been disrupted to produce a relatively small yield of compounds containing sufficient hydrogen to insure that such compounds have the requisite low boiling points.

The history of the art of cracking petroleum reveals that heretofore attempts have been made to simultaneously crack and h drogenate petroleum hydrocarbons, but 1n all cases so far known, the liquid-vapor phase system was employed, and atomic contact between the hydrogen and the hydrocarbons was lacking at the critical moment when the disruption of the heavier molecules of the hydrocarbons began, in consequence of which the degree of hydrogenation effected was very sli ht.

in important object is to crack hydrocarbon oils in atomic contact With hydrogen in such concentrations that the reaction will proceed toward the maximum formation of desired light oils for use as motor fuels.

The history of the art also shows that attempts have been made to hydrogenate the cracked products while the hydrogen and the hydrocarbons are in thevapor phase. But this has been attended by the' usual difficulties inherent to catalytic hydrogenation processes, and it has been found that the cracked products produced by such processes tend to assume a stable form, very diiiicult to hydro-` genate, immediately upon their formation.

The present process may be performed in any suitable apparatus and it is to be understood that the apparatus illustrated in the drawing is merely typical of those that may be employed.

The view is a more or less diagrammatic elevation of an apparatus in which the process may be performed.

In order to describe the process in suiiicient detail, to enable those skilled in the art to perform the process, the apparatus will. now be described as follows.

There is provided a mixing tank 1 which receives the heavier hydrocarbons from a storage tank 2 through a ipe line\3, therel being a pump 4 in the pipe ine 3 to force the hydrocarbons into the mixing tank. lThese hydrocarbons are heavier than the product desired. The mixing tank receives its hydrogen-yielding lighter hydrocarbons from a pipe line 5 which terminates inside of the mixing tank in a series of jets 6 so that as said lighter hydrocarbons enter the mixing tank they will bubble up through the heavier hydrocarbons and thus intimately mix the heavier with the lighter. The lighter hydrocarbons, entering through the pipe line 5 and constituting the source for the hydrogen that is to e'ect hydrogenation of the heavier hydrocarbons, may be any one of the saturated hydrocarbons of the chain series'such as, for example, propane, butane, pentane, or a mixture of two or more of these compounds. These compounds are lighter than the product desired, being too volatile to be used for motor fuel and containing relatively high percentages of hydrogen.

It may be advisable, in some instances, to

employ a catalyst so that the pressure, temperature and time necessary to effect completion of the reactions may be reduced. This catalyst may be a metallic saltl of an organic acid such,for example, as a formate, an acetate or a lactate, or the catalyst may be a carbonyl as, for example, nickel carbonyl.. The metallic salts and the carbonyls are examples of catalytic agents that are miscible in the petroleum so that contact will take place in the liquid phase, thus giving atomic contact. The catalytic agent, for example nickel carbonyl, may be introduced to the mixing tank through the ets 6 and a pipe line 7 leading to said jets.

From the mixing tank 1 the mixture of heavier and lighter hydrocarbons and, if used, the catalytic agent soluble in the oil, pass through a pipe line 8 to a heater 9 Where the temperature of the mixture is raised to the desired degree and the heated mixture then passes intoa digester 10 which is preferably insulated so that the mixture will be maintained at cracking temperature (about 400o C.' or more) for the period of time that the mixture is in the digester. From .the digester the mixture discharges into a pipe line 11 through a pressure controlling valve l 12 which maintains the mixture in the di-` gester under any desired pressure. pressure will be sufficient to maintain the mixture substantially in the liquid phase Within the heater and digester, and very little, if any, carbon will be deposited in the heater or digester. The pipe line 8 is provvided with a pump 13.

The mixture containing the cracked hydrocarbons may pass from the pipe line 11 into a cooler 14 of any desired description and thence through a pipe line 15 to a tank 16 Which constitutes a storage receptacle for the synthetic crude. The pipe line 15 is provided with a pressure valve 17 so as to maintain the desired degree of pressure on the 'cooler 14. The fixed gases are discharged from the tank 16 through a pipe line 18, having a valve 19, to the hydrogen storage tank 20.

The solid residue or precipitate containing metallic sulphides, oxides, undecomposed metallic salts and metal, that collects in the tank 16 is drawn oil' from said tank through a pipe line 21 having a valve 22. The residue thus drawn off may be filtered and further treated in a suitable furnace and any other suitable apparatus to separate the catalytic material from the other substances and to reconvvert said catalytic material into the form in which it is employed in this process so that such reconverted catalytic agent may Abe used again in the process instead of an a still 25 which effects distillation, the v apors l passing from the still 25 through a pi e line l 26 to a condenser 27, and the con ensate passes from the condenser 27 through a pipe Aline 28, having a pressure valve 29, to a receiver 30. Some fixed gases will probably discharge from the receiver 30 through a pipe line 31, having a valve 32, to the pipe line 18, thence into the storage tank 20, and hydrocarbons suitable `for motor fuel will discharge from the receiver 30 through a pipe line 33, having a valve 34, into a gasoline storage tank 35, there being a branch pipe 36 connecting the pipe line 33 with a storage tank 37 for intermediates, which are hydrocarbons too heavy for use as motor fuel and which may be subjected to further distillation by discharging them from the storage tank 37 through a pipe line 38 into a still 39. The pipe line 38 is provided with a valve 40 and in said pipe line is a pump 41. The vapors from the still 39 discharge through a pipeline 42 into a heater or furnace 43 Where vapor phase hydrogenation is effected, the hydrogen being brought into the presence of the d istillates in the heater 43 through a pipe line 44 from the storage tank 20. The pipe line 40 is provided with a valve 45 and in said nipe line is a compressor 46.

The hydrogenated product discharges from the furnace 43 through a pipe line 47 into a condenser 48 and from said condenser through a pipe line 49 into a receiver 50. The

lighter hydrocarbons'relatively high in hy' drogen and, consequently, a source of hydrogen for use in the process in lieu of an equal volume of such hydrocarbons from an outside source discharge from the receiver 50 into the pipe line 5 and thence to the mixing tank 1. The pipe line 5 is provided with valves 51, 52. The condensed motor fuel passes from the receiver 50 through a pipe line 53 to the pipe line 33, thence into the storage tank 35. Y

The heavier hydrocarbons that are not vaporized in the still 25 discharge therefrom through a pipe line 55, having valves 56, 57, into a tank 58 which is a storage container for the cycle stock that is returned as a reflux to the mixing tank 1.

Any free hydrogen gas or hydrogen-bearing gas may be discharged from the mixing tank through a pipe line 60, having a valve 61, to the pipe line 18, thence to the hydrogen storage tank 20. Itis preferable to conne'ct the pipe lines 5, 60 by a pipe line 62 provided Witha valve 63 so that an fixed gases may be discharged from the recelver 50 to the tank 20.

Any carbon monoxide as that may be formed in the mixing tank y decomposition ofnickel carbonyl, Ni(C ).1 for example) may be discharged through a pipe line 64, b

having a valve 65, into a storage tank 66 and this gas may be used in the process of reconditioning the catalyti'c agent employed in this process.

The operation of the process, as carried out in the above described apparatus, may be summarized as follows:

1. Cracking is effected in the heater 9 and digester 10, in substantially liquid phase, of a properly proportioned mixture of (a) liqiid hydrocarbons or hydrocarbona'ceous su stances too heavy for use as motor fuel', as for example, petroleum distillates, petroleum residue, heavy shale oils, coal oils, fuel oil and asphalt as Well as liquid tarry substances such as coal tar or Wood tar; 12) hydrocarbons too light for motor uel as for example, methane, ethane, propane, butane, pentane, and mixtures of 'two or more thereof such as occur in in natural gases; and (c) an oil soluble metallic compound in sufficient quantity to effect desulphurizing and to furnish catalyzing material, as, for example, metallic salts of organic acids, such as formates, acetates and lactates, and carbonyls, such as nickel carbonyl. The mixing of these substances is effected in the mixing tank 1. y

2. The products resulting from the liquid phase crackin are separated and these products are (a) ydrogen and other gases noI condensible at ordinary temperatures and pressures; (b) hydrocarbons suitable for use as motor fuel; (o) hydrocarbons too heavy for motor fuel but vaporizable under pressures near 'atmospheric Without undergoing decomposition; (d) hydrocarbonaceous residuum not vaporizable Without decomposition excepting under a high Vacuum; (e) a precipitate including the metallic sulphides, oxides, undecomposed metallic salts, and metal, which precipitate can be treated by roasting, /reducing and reformation of the organic oil-soluble compounds (10).'

The product (2a) passes from' the tank 16 into the storage tank 20; the product (2b) passes from the receiver 30 into the storage tank 35; the product (20) passes from the re- 'ceiver 30 and still 25 into the storage tank 37; the product (2d) passes from, the still 25 into the storage tank 58; and the product (2e) passes from the tank 16 through the,

plpe line 21 into a suitable apparatus for such treatment as will reform the catalytic material.

3. Certain of the products (2c) mentioned above that otherwise would be by-products are utilized in the process for vapor phase hydrogenation which is effected in the furnace 43,.` This hydrogenation may be efe'cted in the presence of the catalyst recovered from the product (2e) so as to produce (2e) the hydrocarbons too heavy for motor fuel, and hydrocarbons (1b) which are the hydrocarons used as the source of hydrogen in the liquid phase cracking, as they are especially rich in hydrogen.

4. Cracking is effected in the liquid phase and with hydrogenation of the product (2d), the hydrocarbon residuum which is reluxed from the tank 58. This crackin operation is identical with that described a ove under lloo 1 and the products la, 1b, and 1c will result.

From the foregoing it will be understood that the process is completely cyclic and regenerative, that hydrocarbons of any class or boiling point range may be produced by proper control of the pressures and tempera.- tures and by varying the proportions of the lighter and heavier hydrocarbons in the mixture, and that all of the products are completely desulphurized.

I claim:

1. The process of treating hydrocarbons, consisting in mixing together hydrocarbons which are gaseous at ordinary temperatures and pressures and a hydrocarbon oil heavier than the product desired, and a compound of nickel soluble in the hydrocarbons, and subjecting the mixture to temperature and pressure conditionscapable of causing cracking of the hydrocarbons to take place substantially in the liquid phase.

2. The process of treating hydrocarbons, consisting in mixing together hydrocarbons which are gaseous at ordinary temperatures and pressures and hydrocarbon oils which are heavier than the product desired and a compound of nickel soluble in the hydrocarbons, subjecting the mixture to temperature and pressure conditions capable of causing cracking of the hydrocarbons to take place substantially in the liquid phase to produce a synthetic crude, maintaining the synthetic crude under pressure, removing the spent catalyst and the gases from the liquid, distilling the liquid, then separating the heavier and lighter hydrocarbons resulting from the distillation, hydro enatiii some of the resulting heavier hy rocarbons in vapor phase, condensing theD resulting heavier vapors, and returning the lighter uncondensed vapors relatively rich in hydrogen to the process.

3. The process of treating hydrocarbons comprising mixing together hydrocarbons which are gaseous at ordinary temperatures and pressures and a hydrocarbon oil heavier than the product desired, and nickel carbonyl, and subjecting the mixture to temperature and pressure conditions capable of causing cracking of the hydrocarbons to take place substantially in the liquid phase.

Signed at Richmond, Calif., this 4th day of June, 1925.

- RICHARD F. DAVIS. 

